From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793881223; b=5U1c+EYPvNnh60wAiDHdA9jneTSB8ps3P8PlLOD5TtYO0TtjGEVP7kWkAmYRFZp7e8y9 9mARhupwG0kxjs8Un/l8yrWpsz7O7xpgl/klFLWmzz9RnM5ODbM5hIPZn7LNiCMxvI9ro 1vIZFC1Ds1fDIFDxjJgirDt0/8mgphKBN2k+EgYV5D6rYoDp4dtOqdRNMEjCQeKxzB7n1 HiwaTRqm8JrOT3u9XUxt4QJ3YJY5LtRQjTo+GDCl42XsiaVgpO4nE64400K9pqb2p1cHh sV+TFh9auOpEgvR2pyz32dfs+GY4hDOLuLBROa64tBCZUsTEwJbY618iZhhFKEltnDQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793881223; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=fAmo3UiGH3poxS3WQo2PjWtTz2Q8kyx+gsOelyY9Rlo=; b=WFwv7yuzvorlaSJNpqr2LEy1MMOKED1/JB5Ke3WXLa5Tb5JXBA6GSLmhMyaaxf6rZz9g v/Dje6mKgQOuLJJSaHIxSivXAPeegSaDChDpcBLlJWru3+9IMruBR91XYqmRsqzv+XmAi Ezkwg1pBEC6rufih1sU0wxmtvPJym0SzahzgifVQq5xVwvpHf/BA0+f9QcHq06Py0lYV1 iUWsR1lkVHg5yd1i5XgqnzK/fHifGz+On5j+JDYEPoW3NE5eUflnz/yMpn01cr+S8yvQy bm49jlMAWh/eDG5KlWFw3EICtz7oO8rQ2mi5GO4Uxx0Jsh7+rGHGXnL4LCgUCFho9NA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=dL2lpMMy; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0EE30606A329 for ; Thu, 5 Nov 2026 12:20:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=dL2lpMMy Received: by smtp.kernel.org (Postfix) with ESMTPSA id EAEA21F000C1; Thu, 5 Nov 2026 12:20:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793881222; bh=fAmo3UiGH3poxS3WQo2PjWtTz2Q8kyx+gsOelyY9Rlo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=dL2lpMMyshmDMSOm5IlWHYFsLT8naHwzwydssdQCCxXIo7Si60nEuTEAMRwIBcbjg UuLHmZYwZuyn3ICgK1tw3/X2GqZRD0r/euBPTOvMNGGlFomafBsJEZeF/gSmkfXPr8 XeGgnbjOkblCPsXOroj2fv3H+DuWpmZTb4jS1YrUX1IgoehJvs2sjrhYA/YAJxs+Os jx+e8G/HGDIQpWa/qu3AKfI6ChvPkWkBtvkfEik5BQCwCQdzU730u59USJdt5RiCmP SYrkylG0yWfv1p5j4+b53DeKVeQycg67CJleyPJj7ne7nuiijdGdc/YA/6+bP8m8t0 RtC5mKw8ecyeQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Cen Zhang , Andrew Morton , Joseph Qi , Mark Fasheh , Joel Becker , Heming Zhao , Jia-Ju Bai , jjzuming@gmail.com, Sasha Levin Subject: [PATCH 5.10.y] ocfs2: snapshot dentry names in file and setattr traces Date: Thu, 5 Nov 2026 07:20:20 -0500 Message-ID: <20261105121916.1253770-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026110444-uncivil-appraiser-edfc@gregkh> References: <2026110444-uncivil-appraiser-edfc@gregkh> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Cen Zhang [ Upstream commit 8cd3ff30659775a6831c66687a69d2b83d163591 ] Patch series "ocfs2: stabilize dentry names in file and setattr traces", v4. Snapshot names at all six users of ocfs2__file_ops and at the separate setattr event. Patch 1 handles the five ordinary file-operation callers and setattr. Patch 2 handles release separately to preserve its locked open-count sample and take the snapshot outside that critical section. The release explanation distinguishes its existing RCU lifetime coverage from name/length consistency. It does not claim that the ordinary callers' external-name UAF interleaving crosses the held inode spinlock. The release source change is unchanged from v3. Patch 1 also removes the read callback's redundant NULL-inode check. The two patches apply independently and leave trace formats unchanged. This patch (of 2): The open, fsync, read, write and splice-read trace calls pass the live dentry name and length to the shared ocfs2__file_ops event class. ocfs2_setattr() passes the same unprotected arguments to its own event. Both events size and copy a __string field separately. A reference to the dentry does not pin the external storage backing an individual name. With an event enabled, a caller can be preempted after loading the name pointer. A long-to-short rename can then replace the name and reclaim its old external allocation before the trace callback sizes or copies it, provided no other snapshot retains that allocation. The setattr inode lock does not exclude every rename: a same-directory rename of a source directory need not take that directory's inode lock. It can therefore change the dentry name while setattr records its event. Inline names and separately loaded lengths can also change during trace record sizing and copying. Take a dentry name snapshot around each of these six trace calls and pass both the string and length from the snapshot. Check event enablement before taking a snapshot. Keep the event classes and formats unchanged. Also remove the redundant NULL-inode check in the read callback. file_inode() returns the open file's inode, which is already used by the trace call above the check. The historical report below is from the read path. KASAN report as below: BUG: KASAN: slab-use-after-free in strlen+0x85/0xa0 Read of size 1 at addr ffff88810a5b2b18 by task python3/496 [CPU and host details omitted.] Call Trace: dump_stack_lvl+0x93/0xd0 print_report+0xce/0x630 ? strlen+0x85/0xa0 ? srso_alias_return_thunk+0x5/0xfbef5 ? __virt_addr_valid+0x20e/0x420 ? strlen+0x85/0xa0 kasan_report+0xe0/0x110 ? strlen+0x85/0xa0 strlen+0x85/0xa0 trace_event_raw_event_ocfs2__file_ops+0xf0/0x480 ? __pfx_trace_event_raw_event_ocfs2__file_ops+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? pmbd_probe_hit_cookie+0xe7/0x1c0 ? srso_alias_return_thunk+0x5/0xfbef5 ? __pfx_pmbd_probe_hit_cookie+0x10/0x10 ocfs2_file_read_iter+0x6cd/0xb30 ? __pfx_ocfs2_file_read_iter+0x10/0x10 ? selinux_file_permission+0x11d/0x540 ? srso_alias_return_thunk+0x5/0xfbef5 ? security_file_permission+0x26/0x80 vfs_read+0x7d2/0xc20 ? __pfx_vfs_read+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? __pfx_do_sys_openat2+0x10/0x10 ksys_read+0x111/0x200 ? __pfx_ksys_read+0x10/0x10 ? irqentry_exit+0xbe/0x820 ? srso_alias_return_thunk+0x5/0xfbef5 ? trace_hardirqs_on_prepare+0x11d/0x150 ? srso_alias_return_thunk+0x5/0xfbef5 do_syscall_64+0x114/0x620 entry_SYSCALL_64_after_hwframe+0x77/0x7f [User register dump omitted.] Allocated by task 489: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 __kasan_kmalloc+0xaa/0xb0 __kmalloc_noprof+0x2de/0x780 __d_alloc+0x5fc/0x8c0 d_alloc_parallel+0x106/0x11d0 lookup_open+0x3ff/0x13e0 path_openat+0x95e/0x2020 do_file_open+0x21e/0x470 do_sys_openat2+0xf4/0x1b0 __x64_sys_openat+0x136/0x1e0 do_syscall_64+0x114/0x620 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 0: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x60 __kasan_slab_free+0x5f/0x80 __rcu_free_sheaf_prepare+0x65/0x2a0 rcu_free_sheaf_nobarn+0x1d/0x50 rcu_core+0x6be/0x1ed0 handle_softirqs+0x1fa/0x8d0 __irq_exit_rcu+0x113/0x1e0 irq_exit_rcu+0xe/0x20 sysvec_apic_timer_interrupt+0x6c/0x80 asm_sysvec_apic_timer_interrupt+0x1a/0x20 The buggy address belongs to the object at ffff88810a5b2b00 which belongs to the cache kmalloc-rcl-192 of size 192 The buggy address is located 24 bytes inside of freed 192-byte region [ffff88810a5b2b00, ffff88810a5b2bc0) [Page and shadow-memory dumps omitted.] Link: https://lore.kernel.org/pm-ocfs2-objects-candidate-0088-v7-6324344256f0c3b1c3d8-0@gmail.com Link: https://lore.kernel.org/pm-ocfs2-objects-candidate-0088-v7-6324344256f0c3b1c3d8-1@gmail.com Fixes: 468eedde23d6 ("ocfs2: Remove mlog(0) from fs/ocfs2/file.c") Signed-off-by: Cen Zhang Signed-off-by: Andrew Morton Reviewed-by: Joseph Qi Assisted-by: LLM Cc: Mark Fasheh Cc: Joel Becker Cc: Heming Zhao Cc: Jia-Ju Bai Cc: Cc: [ sashal: omitted the ocfs2_file_splice_read() tracing changes ] Signed-off-by: Sasha Levin --- fs/ocfs2/file.c | 84 +++++++++++++++++++++++++++++++------------------ 1 file changed, 53 insertions(+), 31 deletions(-) diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c index 53b5fbaee7f73..c5145ec2fa03c 100644 --- a/fs/ocfs2/file.c +++ b/fs/ocfs2/file.c @@ -86,10 +86,17 @@ static int ocfs2_file_open(struct inode *inode, struct file *file) int mode = file->f_flags; struct ocfs2_inode_info *oi = OCFS2_I(inode); - trace_ocfs2_file_open(inode, file, file->f_path.dentry, - (unsigned long long)oi->ip_blkno, - file->f_path.dentry->d_name.len, - file->f_path.dentry->d_name.name, mode); + if (trace_ocfs2_file_open_enabled()) { + struct dentry *dentry = file->f_path.dentry; + struct name_snapshot name; + + take_dentry_name_snapshot(&name, dentry); + trace_ocfs2_file_open(inode, file, dentry, + oi->ip_blkno, + name.name.len, name.name.name, + mode); + release_dentry_name_snapshot(&name); + } if (file->f_mode & FMODE_WRITE) { status = dquot_initialize(inode); @@ -175,11 +182,17 @@ static int ocfs2_sync_file(struct file *file, loff_t start, loff_t end, tid_t commit_tid; bool needs_barrier = false; - trace_ocfs2_sync_file(inode, file, file->f_path.dentry, - oi->ip_blkno, - file->f_path.dentry->d_name.len, - file->f_path.dentry->d_name.name, - (unsigned long long)datasync); + if (trace_ocfs2_sync_file_enabled()) { + struct dentry *dentry = file->f_path.dentry; + struct name_snapshot name; + + take_dentry_name_snapshot(&name, dentry); + trace_ocfs2_sync_file(inode, file, dentry, + oi->ip_blkno, + name.name.len, name.name.name, + (unsigned long long)datasync); + release_dentry_name_snapshot(&name); + } if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb)) return -EROFS; @@ -1130,15 +1143,19 @@ int ocfs2_setattr(struct dentry *dentry, struct iattr *attr) int had_lock; struct ocfs2_lock_holder oh; - trace_ocfs2_setattr(inode, dentry, - (unsigned long long)OCFS2_I(inode)->ip_blkno, - dentry->d_name.len, dentry->d_name.name, - attr->ia_valid, - attr->ia_valid & ATTR_MODE ? attr->ia_mode : 0, - attr->ia_valid & ATTR_UID ? + if (trace_ocfs2_setattr_enabled()) { + struct name_snapshot name; + + take_dentry_name_snapshot(&name, dentry); + trace_ocfs2_setattr(inode, dentry, OCFS2_I(inode)->ip_blkno, + name.name.len, name.name.name, attr->ia_valid, + attr->ia_valid & ATTR_MODE ? attr->ia_mode : 0, + attr->ia_valid & ATTR_UID ? from_kuid(&init_user_ns, attr->ia_uid) : 0, - attr->ia_valid & ATTR_GID ? + attr->ia_valid & ATTR_GID ? from_kgid(&init_user_ns, attr->ia_gid) : 0); + release_dentry_name_snapshot(&name); + } /* ensuring we don't even attempt to truncate a symlink */ if (S_ISLNK(inode->i_mode)) @@ -2383,11 +2400,17 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb, int direct_io = iocb->ki_flags & IOCB_DIRECT ? 1 : 0; int nowait = iocb->ki_flags & IOCB_NOWAIT ? 1 : 0; - trace_ocfs2_file_write_iter(inode, file, file->f_path.dentry, - (unsigned long long)OCFS2_I(inode)->ip_blkno, - file->f_path.dentry->d_name.len, - file->f_path.dentry->d_name.name, - (unsigned int)from->nr_segs); /* GRRRRR */ + if (trace_ocfs2_file_write_iter_enabled()) { + struct dentry *dentry = file->f_path.dentry; + struct name_snapshot name; + + take_dentry_name_snapshot(&name, dentry); + trace_ocfs2_file_write_iter(inode, file, dentry, + OCFS2_I(inode)->ip_blkno, + name.name.len, name.name.name, + (unsigned int)from->nr_segs); + release_dentry_name_snapshot(&name); + } if (!direct_io && nowait) return -EOPNOTSUPP; @@ -2533,17 +2556,16 @@ static ssize_t ocfs2_file_read_iter(struct kiocb *iocb, int direct_io = iocb->ki_flags & IOCB_DIRECT ? 1 : 0; int nowait = iocb->ki_flags & IOCB_NOWAIT ? 1 : 0; - trace_ocfs2_file_read_iter(inode, filp, filp->f_path.dentry, - (unsigned long long)OCFS2_I(inode)->ip_blkno, - filp->f_path.dentry->d_name.len, - filp->f_path.dentry->d_name.name, - to->nr_segs); /* GRRRRR */ - + if (trace_ocfs2_file_read_iter_enabled()) { + struct dentry *dentry = filp->f_path.dentry; + struct name_snapshot name; - if (!inode) { - ret = -EINVAL; - mlog_errno(ret); - goto bail; + take_dentry_name_snapshot(&name, dentry); + trace_ocfs2_file_read_iter(inode, filp, dentry, + OCFS2_I(inode)->ip_blkno, + name.name.len, name.name.name, + to->nr_segs); + release_dentry_name_snapshot(&name); } if (!direct_io && nowait) -- 2.53.0